Geoscience Reference
In-Depth Information
Chapter 1
Dynamic planet
Once a photograph of the Earth, taken from the outside, is available, a new
idea as powerful as any in history will be let loose.
Sir Fred Hoyle, 1948
How can you put a big round planet in a small flat topic? It is not an easy fit, but there could
be two broadly different ways of attempting it. One is the bottom-up approach of geology:
essentially, looking at the rocks. For centuries, geologists have scurried around on the sur-
face of our planet with their little hammers examining the different rock types and the min-
eral grains which make them up. With eye and microscope, electron probe and mass spectro-
meter, they have reduced the planet's crust to its component parts. Then they have mapped
out how the different rock types relate to one another and, through theory, observation, and
experiment they have worked out how they might have got there. It has been a huge under-
taking and one that has brought deep insights. Collectively, the efforts of all those geologists
have built a giant edifice on which future earth scientists can stand. It's as a result of this
bottom-up approach that I can write this topic. But it is not the approach I will use. This is
not a guide to rocks and minerals and geological map-making. It is a portrait of a planet.
The new view on our old planet is the top-down approach of what has come to be known
as Earth systems science. It looks at the Earth as a whole and not just frozen in time in the
moment we call now. Taken over the deep time of geology we begin to see our planet as a
dynamic system, a series of processes and cycles. We can begin to understand what makes it
tick.
The view from above
The prediction above was made by astronomer Sir Fred Hoyle in 1948, a decade before the
dawn of space flight. When unmanned rockets took the first pictures of the Earth from out-
side, and when the first generation of astronauts saw for themselves our world in its entirety,
the prediction came true. It's not that those first views told us much we didn't already know
about the Earth, but they gave us an icon. And to many of the astronauts who witnessed the
view first-hand, it gave an emotional experience of the beauty and seeming fragility of our
world that has lived with them ever since. It is perhaps no coincidence that Earth sciences
